U.S. patent application number 16/545422 was filed with the patent office on 2021-02-25 for composite skid members.
The applicant listed for this patent is Bell Textron Inc. Invention is credited to William Anthony Amante, Timothy Brian Carr, Brian John Cox.
Application Number | 20210053674 16/545422 |
Document ID | / |
Family ID | 1000004749830 |
Filed Date | 2021-02-25 |
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United States Patent
Application |
20210053674 |
Kind Code |
A1 |
Carr; Timothy Brian ; et
al. |
February 25, 2021 |
COMPOSITE SKID MEMBERS
Abstract
Various implementations directed to composite skid members are
provided. In one implementation, an aircraft landing gear assembly
may include two skid members configured to contact the ground,
where each skid member includes composite material manufactured
using a pultrusion process. The aircraft landing gear assembly may
also include a plurality of cross members configured to couple to a
fuselage of an aircraft and configured to interconnect the two skid
members.
Inventors: |
Carr; Timothy Brian; (Fort
Worth, TX) ; Amante; William Anthony; (Grapevine,
TX) ; Cox; Brian John; (Keller, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bell Textron Inc |
Fort Worth |
TX |
US |
|
|
Family ID: |
1000004749830 |
Appl. No.: |
16/545422 |
Filed: |
August 20, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B64C 27/04 20130101;
B29C 70/545 20130101; B64C 25/52 20130101; B29K 2307/04 20130101;
B29L 2031/3088 20130101; B29L 2031/3082 20130101; B29C 70/52
20130101 |
International
Class: |
B64C 25/52 20060101
B64C025/52; B64C 27/04 20060101 B64C027/04; B29C 70/52 20060101
B29C070/52; B29C 70/54 20060101 B29C070/54 |
Claims
1. An aircraft landing gear assembly, comprising: two skid members
configured to contact the ground, wherein each skid member
comprises composite material manufactured using a pultrusion
process; and a plurality of cross members configured to couple to a
fuselage of an aircraft and configured to interconnect the two skid
members.
2. The aircraft landing gear assembly of claim 1, wherein the
plurality of cross members comprises a front cross member and a
rear cross member.
3. The aircraft landing gear assembly of claim 1, wherein the
composite material comprises carbon fiber reinforced polymer.
4. The aircraft landing gear assembly of claim 1, wherein each skid
member has a constant cross-section throughout its length.
5. The aircraft landing gear assembly of claim 1, further
comprising a scuff guard coupled to each skid member, wherein the
scuff guard is configured to surround at least a bottom portion of
each skid member.
6. The aircraft landing gear assembly of claim 5, wherein the scuff
guard is composed of steel.
7. The aircraft landing gear assembly of claim 1, wherein the
plurality of cross members is composed of metallic material.
8. The aircraft landing gear assembly of claim 1, wherein the
plurality of cross members is made of an aluminum alloy.
9. The aircraft landing gear assembly of claim 1, wherein the
aircraft comprises a helicopter.
10. The aircraft landing gear assembly of claim 1, wherein the
composite material manufactured using the pultrusion process
comprises composite material manufactured by: pulling reinforcement
material through an impregnation mechanism; impregnating the
reinforcement material with resin; curing the impregnated
reinforcement material using a die to form a cured product; and
cutting the cured product at a predetermined length to form a
respective skid member.
11. An aircraft, comprising: a fuselage; an aircraft landing gear
assembly, comprising: two skid members configured to contact the
ground, wherein each skid member comprises composite material; and
a plurality of cross members configured to couple to the fuselage
and configured to interconnect the two skid members.
12. The aircraft of claim 11, wherein each skid member comprises
composite material manufactured using a pultrusion process.
13. The aircraft of claim 11, wherein the composite material
comprises carbon fiber reinforced polymer.
14. The aircraft of claim 11, wherein the aircraft landing gear
assembly further comprises a scuff guard coupled to each skid
member, wherein the scuff guard is configured to surround at least
a bottom portion of each skid member.
15. The aircraft of claim 11, wherein the plurality of cross
members is composed of metallic material.
16. The aircraft of claim 11, wherein each skid member comprises
composite material is manufactured by: pulling reinforcement
material through an impregnation mechanism; impregnating the
reinforcement material with resin; curing the impregnated
reinforcement material using a die to form a cured product; and
cutting the cured product at a predetermined length to form a
respective skid member.
17. A method, comprising: pulling continuous reinforcement material
through an impregnation mechanism to impregnate the continuous
reinforcement material with resin; pulling the impregnated
continuous reinforcement material through a curing die to form a
cured product; and cutting the cured product into predetermined
lengths to form one or more pultruded composite skid members for
use with an aircraft landing gear assembly.
18. The method of claim 17, wherein: the continuous reinforcement
material comprises continuous carbon fibers; and the impregnation
mechanism comprises a closed injection die with one or more resin
injection ports, wherein the resin is injected under pressure
through the one or more resin injection ports to impregnate the
continuous carbon fibers.
19. The method of claim 18, wherein: the curing die is configured
to apply heat to the impregnated continuous carbon fibers to form
the cured product; and the shape of the cured product is based on a
shape of the curing die.
20. The method of claim 17, further comprising coupling the one or
more pultruded composite skid members with one or more metallic
cross members for use with the aircraft landing gear assembly.
Description
[0001] STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
[0002] Not applicable.
BACKGROUND
[0003] This section is intended to provide background information
to facilitate a better understanding of various technologies
described herein. As the section's title implies, this is a
discussion of related art. That such art is related in no way
implies that it is prior art. The related art may or may not be
prior art. It should therefore be understood that the statements in
this section are to be read in this light, and not as admissions of
prior art.
[0004] The landing gear used by aircraft may be configured to
support the aircraft on the ground and allow the aircraft to taxi,
takeoff, and/or land. For some aircraft, such as helicopters or
other rotorcraft, the landing gear may be a skid landing gear. The
skid landing gear may provide energy attenuation in various types
of landings, including normal landings, hard landings,
auto-rotations, and crash landings. In addition, the skid landing
gear may be dynamically tuned to avoid ground resonance, such as in
roll and shuffle modes.
[0005] Conventional skid landing gear may include a pair of cross
members attached to a pair of skid members. Some skid members may
be made from aluminum extrusions or seamless drawn aluminum tubes,
where the skid members may also be chemically milled in order to
reduce weight where possible. However, chemical milling may present
environmental complications and may require a relatively long lead
time for manufacturing. Thus, the design of a cost-effective,
environmentally sensitive, and relatively lightweight landing gear
that requires less manufacturing time has presented challenges to
engineers and manufacturers.
SUMMARY
[0006] Described herein are implementations of various technologies
relating to composite skid members. In one implementation, an
aircraft landing gear assembly may include two skid members
configured to contact the ground, where each skid member includes
composite material manufactured using a pultrusion process. The
aircraft landing gear assembly may also include a plurality of
cross members configured to couple to a fuselage of an aircraft and
configured to interconnect the two skid members.
[0007] In another implementation, an aircraft may include a
fuselage and an aircraft landing gear assembly. The aircraft
landing gear assembly may include two skid members configured to
contact the ground, where each skid member includes composite
material. The aircraft landing gear assembly may also include a
plurality of cross members configured to couple to the fuselage and
configured to interconnect the two skid members.
[0008] In yet another implementation, a method may include pulling
continuous reinforcement material through an impregnation mechanism
to impregnate the continuous reinforcement material with resin. The
method may also include pulling the impregnated continuous
reinforcement material through a curing die to form a cured
product. The method may further include cutting the cured product
into predetermined lengths to form one or more pultruded composite
skid members for use with an aircraft landing gear assembly.
[0009] The above referenced summary section is provided to
introduce a selection of concepts in a simplified form that are
further described below in the detailed description section. The
summary is not intended to identify key features or essential
features of the claimed subject matter, nor is it intended to be
used to limit the scope of the claimed subject matter. Furthermore,
the claimed subject matter is not limited to implementations that
solve any or all disadvantages noted in any part of this
disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] Implementations of various techniques will hereafter be
described with reference to the accompanying drawings. It should be
understood, however, that the accompanying drawings illustrate only
the various implementations described herein and are not meant to
limit the scope of various techniques described herein.
[0011] FIG. 1 illustrates a schematic diagram of an aircraft in
accordance with implementations of various techniques described
herein.
[0012] FIG. 2 illustrates a partial schematic diagram of a landing
gear assembly in accordance with implementations of various
techniques described herein.
[0013] FIG. 3 illustrates a schematic diagram of a system for
producing a composite skid member using a pultrusion process in
accordance with implementations of various techniques described
herein.
[0014] FIG. 4 illustrates a flow diagram of a method 400 for
producing a composite skid member using a pultrusion process in
accordance with implementations of various techniques described
herein.
DETAILED DESCRIPTION
[0015] Various implementations directed to composite skid members
will now be described in the following paragraphs with reference to
FIGS. 1-4.
[0016] As noted above, aircraft may use skid landing gear, where
the skid landing gear may be configured to support the aircraft on
the ground, allow the aircraft to taxi, takeoff, and/or land,
provide energy attenuation in various types of landings, and may be
dynamically tuned to avoid critical ground resonance modes.
[0017] For example, FIG. 1 illustrates a schematic diagram of an
aircraft 100 in accordance with implementations of various
techniques described herein. As shown, the aircraft 100 may include
a fuselage 120 having a cabin portion 140 and a tail boom 160. The
aircraft 100 as depicted in FIG. 1 is a helicopter, though those
skilled in the art will understand that the implementations
described herein may be applied to any type of aircraft, including,
but not limited to, other types of rotorcraft (e.g., gyrocopters),
ultralight aircraft, vertical take-off and landing (VTOL) aircraft,
sport aviation aircraft, military aircraft, general aviation
aircraft, or commercial passenger aircraft. Further, the aircraft
100 may be powered by one or more engines, a propulsion system such
as a rotor system, and a flight control system.
[0018] In addition, a landing gear assembly 200 may be coupled to a
bottom portion of the fuselage 120. The landing gear assembly 200
may be composed of structural members, such as two longitudinal
skid members 220, a front cross member 240, and a rear cross member
260.
[0019] The longitudinal skid members 220 may be configured to
contact the ground. The longitudinal direction of the skid members
220 is indicated by the longitudinal axis L shown in FIG. 1, where
the axis L is horizontal and parallel to a horizontal ground
surface when the aircraft 100 rests on the ground surface. The
front and rear cross members 240, 260 may be coupled to the
fuselage 120 using any fittings (not shown) known to those skilled
in the art, where the fittings may be external or internal to the
fuselage 120. The cross members 240, 260 may be used to
interconnect the two skid members 220. In particular, the
longitudinal skid members 220 and the cross members 240, 260 may
together be configured to provide energy attenuation for various
landings of the aircraft 100, such as through elastic and plastic
deformation of the cross members 240, 260.
[0020] FIG. 2 illustrates a partial schematic diagram of the
landing gear assembly 200 in accordance with implementations of
various techniques described herein. In particular, FIG. 2
illustrates one half of the landing gear assembly 200, where one
skid member 220 and portions of the cross members 240, 260 are
displayed.
[0021] Those skilled in the art will understand that the other half
of the landing gear assembly 200 is a mirror image of the assembly
200 shown in FIG. 2, such that another skid member 220 is included
and each cross member 240, 260 is symmetrical about a central line
C of the fuselage 120. Though not shown in FIG. 2, those skilled in
the art will understand the front cross member 240 and the rear
cross member 260 may each be in the shape of arches.
[0022] As noted above, conventional skid members may be
manufactured from aluminum extrusions or seamless drawn aluminum
tubes, where chemical milling may be used to reduce the weight of
the skid members where possible. Chemical milling, however, may
lead to environmental issues, increase manufacturing time, and the
like.
[0023] As such, various implementations described herein may
include the use of skid members 220 manufactured using composite
material. Composite material may refer to material formed by
combining two or more constituent materials with different physical
or chemical properties that, when combined, produce a material with
characteristics different from the individual components. Composite
material may include reinforced polymers, such as fiberglass or
fiber-reinforced polymers. One example of fiber-reinforced polymers
may include carbon fiber reinforced polymers.
[0024] Composite material, such as carbon fiber reinforced
polymers, may be relatively high in strength and low in weight,
particularly when compared to metallic material, such as aluminum
alloys. Accordingly, by using skid members 220 composed of
composite material, such as carbon fiber reinforced polymers,
chemical milling and its associated issues (e.g., environmental
complications, increased manufacturing time, and the like) may be
avoided. A skid member made of composite material may hereinafter
be referred to as a composite skid member.
[0025] Various implementations for manufacturing a composite skid
member 220 may be used. For example, such a skid member 220 may be
fabricated using a filament winding process, a fiber placement
process, a hand lay-up process, or the like. In one implementation,
a composite skid member 220 may be manufactured using a pultrusion
process. A composite skid member manufactured using a pultrusion
process may hereinafter be referred to as a pultruded composite
skid member. Compared to other methods for manufacturing composite
material, a pultrusion process may be faster and more automated. As
such, a pultrusion process may be relatively more
cost-effective.
[0026] In one such implementation, the pultrusion process may
include pulling reinforcement material, such as fibers (e.g.,
carbon fibers), through an impregnation mechanism (e.g., an
atmospheric pressure bath) to impregnate it with a curable liquid
resin. Once impregnated, the material may be pulled through a
curing die to polymerize and set the resin, thereby yielding a
product of composite material (e.g., carbon fiber reinforced
polymer). The product may be cut to specific lengths using a saw or
a similar device to form the pultruded composite skid member 220.
Various implementations for the pultrusion process are described in
more detail below.
[0027] In one implementation, a pultruded composite skid member 220
may have a constant cross-section throughout the length of the
member 220, where the cross-section may be circular, rectangular,
or any other shape known to those skilled in the art. In a further
implementation, each pultruded composite skid member 220 may also
have a scuff guard 280 coupled thereto, where the scuff guard 280
may be used to minimize wear on a pultruded composite skid member
220 by protecting the member 220 during landings and while the
aircraft 100 is positioned on the ground. Each scuff guard 280 may
be in the form of a shoe that is configured to surround at least a
bottom portion of a pultruded composite skid member 220. Each scuff
guard 280 may be coupled to a pultruded composite skid member 220
using any implementations known to those skilled in the art,
including, but not limited to, screws, bolts, rivets, and the like.
In one implementation, the scuff guards 280 may be composed of
steel.
[0028] Further, the cross members 240, 260 may be coupled to the
pultruded composite skid members 220 using any implementations
known to those skilled in the art, including, but not limited to,
screws, bolts, rivets, sleeves, saddles, and the like. The
cross-sections of cross members 240, 260 may circular, rectangular,
and/or any other shape known to those skilled in the art. In one
implementation, the cross members 240, 260 may be made of metallic
material. As such, the landing gear assembly 200 may include
metallic cross members 240, 260 coupled to pultruded composite skid
members 220. In one example, the landing gear assembly 200 may
include cross members 240, 260 made of an aluminum alloy (e.g.,
7075-T73511 or 7075-T6511), where the cross members 240, 260 are
coupled to pultruded composite skid members 220 made of carbon
fiber reinforced polymers.
[0029] FIG. 3 illustrates a schematic diagram of a system 300 for
producing a composite skid member 220 using a pultrusion process in
accordance with implementations of various techniques described
herein. Though FIG. 3 illustrates a particular configuration for
the system 300, those skilled in the art will understand that other
configurations for producing a composite skid member may be
used.
[0030] As noted above, the composite material formed in a
pultrusion process may include a fibrous reinforcement material
(e.g., glass, polymeric, carbon fibers, or the like) embedded in a
resin matrix (e.g., polyester, polyurethane, epoxy, or the like).
The fibrous reinforcement material may initially be in various
formations, including, but not limited to, a roving, tow, mat,
woven, or stitched format.
[0031] For example, FIG. 3 illustrates that continuous carbon
fibers may be in the form of fiber tows 310 that are provided on
spools 322, where the spools 322 may be arranged on a fixture such
as a creel 320. The spools 322 may be configured to allow each tow
310 to be fed through the creel 120 without interference or
tangling. For example, the creel 320 may include a series of holes
arranged in a manner such that the fiber tows 310 do not contact
each other as they are being fed through the creel 320. The fiber
tows 310 may be fed through a guide 332 of an infeed structure 330,
where the guide 332 includes a plurality of apertures through which
the fiber tows 310 may be fed in a pattern that is consistent with
the final design shape of the composite skid member 220 to be
manufactured.
[0032] As mentioned above, the reinforcement material may be pulled
through an impregnation mechanism to impregnate it with a curable
liquid resin. In one implementation, the impregnation mechanism may
be an atmospheric pressure bath (e.g., an open bath). In another
implementation, the impregnation mechanism may be a closed
injection die with resin injection ports, where the resin is
injected under pressure through the ports to impregnate the
reinforcement material.
[0033] For example, FIG. 3 illustrates that the fiber tows 310 fed
through the infeed structure 330 may enter an injection die 350,
where the injection die 350 may be configured to coat individual
filaments within each fiber tow 310 with resin using one or more
resin injection ports 348. The resin used may include any that are
known to those skilled in the art, including, but not limited to,
polyester, polyurethane, and epoxy. The resin may be used to
provide environmental resistance for the composite material, while
the reinforcement material may be used to provide strength for the
composite material.
[0034] The impregnated reinforcement material may then be pulled
into a curing or heating die, where the resin may solidify and be
cured within the die. The curing die may apply heat to the
impregnated reinforcement material using any heating
implementations known to those skilled in the art.
[0035] For example, FIG. 3 illustrates that a curing die 360 may be
positioned next to the injection die 350 such that the impregnated
carbon fiber tows 310 may be pulled into the curing die 360 for
heat to be applied to the material. The die 360 may be composed of
any suitable metal, such as steel, and may use any heating elements
known in the art, such as electric heaters. A rigid, cured profile
of the product 312 exiting the die 360 may be formed based on the
shape of the die 360, where the product 312 may be a carbon fiber
reinforced polymer. Further, the cured product 312 exiting the die
360 may be allowed to cool. As shown in FIG. 3, the cured product
312 may be extracted from the curing die 360 using a puller 370.
The puller 370 may be any pulling mechanism known to those skilled
in the art, including, but not limited to, reciprocating pulling
systems or caterpillar-like pulling systems.
[0036] The cured product may then be cut to specific lengths using
a saw or a similar device. For example, FIG. 3 illustrates that a
saw 180 may be used to cut the cured product 312 (i.e., carbon
fiber reinforced polymer) into defined lengths such that a
pultruded composite skid member 220 may be formed, where the skid
member 220 is made of carbon fiber reinforced polymer. In some
implementations, the operation of the system 300 may be automated,
such as through the use of one or more computing systems (not
shown). Further, once two pultruded composite skid members 220 have
been fabricated, the skid members 220 may then be coupled to
metallic cross members 240, 260 to form the landing gear assembly
200 described above.
[0037] FIG. 4 illustrates a flow diagram of a method 400 for
producing a composite skid member using a pultrusion process in
accordance with implementations of various techniques described
herein. In one implementation, method 400 may be at least partially
performed by a computing system or may be performed using a system,
such as system 300, described above. It should be understood that
while method 400 indicates a particular order of execution of
operations, in some implementations, certain portions of the
operations might be executed in a different order. Further, in some
implementations, additional operations or steps may be added to the
method 400. Likewise, some operations or steps may be omitted.
[0038] At block 410, a system may pull continuous reinforcement
material through an impregnation mechanism to impregnate the
continuous reinforcement material with resin. In one
implementation, the continuous reinforcement material may be
continuous carbon fibers in the form of fiber tows. In a further
implementation, the impregnation mechanism may be a closed
injection die with resin injection ports, where the resin is
injected under pressure through the ports to impregnate the
continuous carbon fibers. The continuous carbon fibers may also be
pulled using a pulling mechanism of the system.
[0039] At block 420, a system may pull the impregnated continuous
reinforcement material into a curing die in order to cure the
material. In one implementation, the curing die may apply heat to
the impregnated carbon fibers, forming a rigid, cured product with
a shape based on the shape of the die.
[0040] At block 430, a system may cut the cured material into
predetermined lengths to form one or more pultruded composite skid
members. In one implementation, a saw may be used to cut the cured
material. The one or more pultruded composite skid members may then
be coupled to one or more cross members to form a landing gear
assembly.
[0041] In sum, the implementations disclosed herein may be used to
utilize landing gear having composite skid members. By using such
skid members, chemical milling and its associated issues (e.g.,
environmental complications, increased manufacturing time, and the
like) may be avoided. In addition, composite skid members, such as
those composed of carbon fiber reinforced polymers, may be
relatively high in strength and low in weight when compared to
metallic skid members. Furthermore, compared to other methods for
manufacturing composite material, a pultrusion process may be
faster and more automated. As such, using pultruded composite skid
members may be relatively cost-effective when compared to other
composite skid members.
[0042] The discussion above is directed to certain specific
implementations. It is to be understood that the discussion above
is only for the purpose of enabling a person with ordinary skill in
the art to make and use any subject matter defined now or later by
the patent "claims" found in any issued patent herein.
[0043] It is specifically intended that the claimed invention not
be limited to the implementations and illustrations contained
herein, but include modified forms of those implementations
including portions of the implementations and combinations of
elements of different implementations as come within the scope of
the following claims. It should be appreciated that in the
development of any such actual implementation, as in any
engineering or design project, numerous implementation-specific
decisions may be made to achieve the developers' specific goals,
such as compliance with system-related and business related
constraints, which may vary from one implementation to another.
Moreover, it should be appreciated that such a development effort
might be complex and time consuming, but would nevertheless be a
routine undertaking of design, fabrication, and manufacture for
those of ordinary skill having the benefit of this disclosure.
Nothing in this application is considered critical or essential to
the claimed invention unless explicitly indicated as being
"critical" or "essential."
[0044] In the above detailed description, numerous specific details
were set forth in order to provide a thorough understanding of the
present disclosure. However, it will be apparent to one of ordinary
skill in the art that the present disclosure may be practiced
without these specific details. In other instances, well-known
methods, procedures, components, circuits and networks have not
been described in detail so as not to unnecessarily obscure aspects
of the embodiments.
[0045] It will also be understood that, although the terms first,
second, etc. may be used herein to describe various elements, these
elements should not be limited by these terms. These terms are only
used to distinguish one element from another. For example, a first
object or step could be termed a second object or step, and,
similarly, a second object or step could be termed a first object
or step, without departing from the scope of the invention. The
first object or step, and the second object or step, are both
objects or steps, respectively, but they are not to be considered
the same object or step.
[0046] The terminology used in the description of the present
disclosure herein is for the purpose of describing particular
implementations only and is not intended to be limiting of the
present disclosure. As used in the description of the present
disclosure and the appended claims, the singular forms "a," "an"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise. It will also be understood
that the term "and/or" as used herein refers to and encompasses any
and all possible combinations of one or more of the associated
listed items. It will be further understood that the terms
"includes," "including," "comprises" and/or "comprising," when used
in this specification, specify the presence of stated features,
integers, steps, operations, elements, and/or components, but do
not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components and/or
groups thereof.
[0047] As used herein, the term "if" may be construed to mean
"when" or "upon" or "in response to determining" or "in response to
detecting," depending on the context. Similarly, the phrase "if it
is determined" or "if [a stated condition or event] is detected"
may be construed to mean "upon determining" or "in response to
determining" or "upon detecting [the stated condition or event]" or
"in response to detecting [the stated condition or event],"
depending on the context. As used herein, the terms "up" and
"down"; "upper" and "lower"; "upwardly" and "downwardly"; "below"
and "above"; and other similar terms indicating relative positions
above or below a given point or element may be used in connection
with some implementations of various technologies described
herein.
[0048] While the foregoing is directed to implementations of
various technologies described herein, other and further
implementations may be devised without departing from the basic
scope thereof. Although the subject matter has been described in
language specific to structural features and/or methodological
acts, it is to be understood that the subject matter defined in the
appended claims is not limited to the specific features or acts
described above. Rather, the specific features and acts described
above are disclosed as example forms of implementing the
claims.
* * * * *